ACDelco 41-993 Professional Iridium Spark Plug (Pack of 1) Iridium offers excellent engine idle stability and smooth performance Iridium allows for small, efficient electrode designs for reliable cold starting and quick acceleration Iridium fine-wire electrode helps burn away carbon deposits on the tip of the plug as they form One piece suppressor seal helps block radio frequencies that can affect vehicle electronics Suppressor seal meters spark energy for long electrode life and helps prevent combustion leakage